1. Field of the Invention
The invention relates to a method and apparatus for accessing a data network through a communication system and in particular for accessing the Internet through a cellular communication system.
2. Description of the Related Art
In the last decade, private and public data networks have become increasingly widespread. In particular, the popularity of the Internet has increased explosively and currently a large and increasing proportion of households have Internet access.
Originally private Internet access was typically achieved through the use of a dial-up modem that sets up a data connection to an access provider through a phone line. For dial-up modems, each Internet provider typically has dedicated telephone numbers which are called by the dial-up modem to provide the Internet connection.
Increasingly dial-up modems are being replaced by other access equipment providing improved quality of service to the user. Cable modems and ADSL (Asynchronous Digital Subscriber Line) modems are increasingly being used to provide Internet access as these allow significantly better quality of service and in particular higher achievable data rates and increased connection reliability. In contrast to the dial-up modems, these modems utilize packet data technology thereby allowing an always-on connection without requiring a dedicated connection being continuously active.
Recently, systems for providing wireless access using wireless access equipment have emerged. Such wireless access facilitates distribution and may reduce infrastructure cost as there is no requirement for expensive physical connections to be implemented for the individual user thereby allowing the operator efficiently and cost effectively to offer service to customers throughout a marketplace. Furthermore, the wireless access may provide mobility thereby freeing the user terminal from being tied to a fixed location.
Wireless data systems have been proposed which utilize cellular communication technology implementing an access network for data networks such as the Internet. Such an approach provides the advantages of utilizing a detailed, standardized and flexible technology for providing access to the data network. Furthermore, cellular technologies provide a high spectral efficiency and a wide coverage using relatively few base stations thereby reducing infrastructure cost.
Such a system may advantageously be based on packet data functionality of a cellular communication system such as the Universal Mobile Telecommunication System (UMTS) or Global System for Mobile communications (GSM). UMTS has been standardized in the 3rd Generation Partnership Project (3GPP) Technical Specifications which provide for a range of data services including packet data services suitable for providing appropriate services to a user.
GSM is currently the most ubiquitous cellular communication system. GSM is known as a 2nd generation cellular communication system and originally did not support packet data communications services. However, to further enhance the services and performance of the GSM communication system, a number of enhancements and additions have been introduced to the GSM communication system over the years.
One such enhancement is the General Packet Radio System (GPRS), which is a system developed for enabling packet data based communication in a GSM communication system. The GPRS system is compatible with the GSM (voice) system and provides a number of additional services which augments and complements the circuit switched communication of a traditional communication system. The GPRS system has been standardized as an add-on to an existing GSM communication system, and can be introduced to an existing GSM communication system by introducing new network elements. For example, a number of Serving GPRS Support Nodes (SGSN) and Gateway GPRS Support Nodes (GGSN) may be introduced to provide a packet based fixed network communication. Furthermore, the network of a UMTS communication system is built around GGSNs and SGSNs thereby providing network compatibility between the systems.
In systems such as UMTS and GSM GPRS, it is necessary to initiate services in accordance with the specifications of the cellular communication services. For example, for systems such as UMTS, data packet sessions are set up for a given user by using an access point name. The access point name is an indication of the destination point for a data session for the access equipment. For example, the access point name refers to a Gateway GPRS Support Node (GGSN) providing an interface to the external data network such as the Internet. The use and format of the access point name in UMTS is further defined in 3GPP TS 23.003 v6.2.0 (2004-03) “3rd Generation Partnership Project; Technical Specification Group Core Network; Numbering, addressing and identification (Release 6).”
When setting up a new session for terminal equipment, such as a personal computer (PC), the access equipment must provide the correct access point name identifying the destination GGSN. Typically, the access point name depends on the service provider. In some systems, the access equipment may have a permanently stored access point name corresponding to a service provider. For example, if a wireless modem is supplied by a given service provider, this may have an access point name stored in Read Only Memory (ROM). When the modem receives commands to set up an Internet session, the stored access point name is retrieved and used to identify the destination GGSN.
In some systems, the access point name may be loaded into the access equipment from the terminal equipment. For example, an installation program associated with the modem may download the access point name from a PC to the wireless modem during installation. This may allow a manufacturer to provide the same modem to different Internet service providers together with a customized installation disk that comprises the appropriate access point name for that Internet service provider.
In order to provide backwards compatibility, it is preferable that commands suitable for a dial-up modem may also be used for the wireless access equipment. Therefore, the wireless access equipment may operable to instigate a data session in response to receiving a dial-up command requesting that the modem performs a dial-up.
For example, in Technical Specification 3GPP TS 27.007 v6.4.0 (2003-09) “3rd Generation Partnership Project; Technical Specification Group Terminals; AT command set for User Equipment (UE) (Release 6),” 3GPP has made provision for use of the AT (attention) command set, which is an international standard for terminal to modem interface control. The extended command range AT+C is reserved by the International Telecommunication Union (ITU) for use with GSM/UMTS mobile equipment in ITU-T Recommendation V.25ter.
In accordance with the Technical Specifications, standard AT commands must be supported by GSM/UMTS User Equipment (UE) but can optionally be ignored in some cases. For example, the Technical Specifications provide for the use of the AT command AT+CGDCONT to feed an access point name to wireless access equipment. Thus, during installation of a wireless access system, a PC may download an access point name of the service provider to the wireless access equipment by sending an AT+CGDCONT command.
The standard AT dial command ATD is defined in 3GPP to be used to send a defined string for making a call or controlling supplementary services such as call divert. The Technical Specifications, for example, prescribe that when the wireless access equipment receives an ATD command with a dial string of <*99#>, a new data session should be instigated using the stored access point name. Accordingly, the wireless access equipment proceeds to set up a Packet Data Protocol (PDP) context for the data session using the stored access point name. As part of the setup process, the cellular communication system determines the appropriate point of accessing the Internet in response to the received access point name.
The access point name is typically a domain name associated with the service provider. For example, an access point name of “IPWireless.com” or “aol.com” may be sent to the cellular communication system which in response determines the appropriate GGSN for accessing the Internet via the appropriate Internet service provider.
Hence, a conventional wireless access system allows for standard dial-up commands to be used to access a data network such as the Internet through a cellular communication system. However, the approach tends to be very inflexible and is not user friendly. For example, setting up the wireless access equipment to use the appropriate access point name is cumbersome, inflexible and not user friendly and tends to be performed by an installation program having specified parameters. For example, it is impossible, impractical or cumbersome for a user to change from one service provider to another as this requires a reconfiguration of the wireless access equipment.
This is becoming a considerable disadvantage as it becomes increasingly common for a user to employ a plurality of Internet service providers. For example, the same PC may be used both privately and professionally with different Internet service providers being used for each purpose. However, reconfiguring the wireless access equipment, e.g., by running an installation program every time a user switches between the service providers, is highly impractical. Similarly, setting up wireless access equipment with a new Internet service provider may result in existing applications malfunctioning as these may be specific for a previous Internet service provider.
Hence, an improved system for accessing a data network through a cellular communication system would be advantageous and in particular a system allowing increased flexibility, increased user friendliness and/or improved performance would be advantageous.